Butler wrote the lyrics of "Black Sabbath" and has significantly influenced the style of the band through his lyrics. He was one of the first bassists to use the wah-wah effect.This effect pedal and its lower tuned bass have inspired many well-known bass players to use the device and the corresponding settings as well. In the meantime, the lower parts are a stylistic device that is characteristic of metal bands.
Happy Birthday Geezer Butler